The isolated rabbit retina will be used as a prototype of brain for 3 collaborative studies. The first study will use isotopically labelled amino acids to measure rates of protein synthesis and breakdown in order to examine some of the interrelationships between the functional state of CNS cells and their protein metabolism. The second study will measure the response of the several neuronal circuits in the retina to agents that potentiate or inhibit specific neurotransmitters in order to obtain information about the transmitters normally involved in these circuits. The third study will examine the retina's response to, and recovery from, short periods of ischemia to find out more about the mechanisms of the ischemic insult and to attempt to identify what chemical or structural change limits recovery. BIBLIOGRAPHIC REFERENCES: Steinman, L. and Ames, A. III. The sites of synthesis and the subsequent migration of newly synthesized protein in retina. Tissue & Cell 6:137-152, 1974. Masland, R.H. and Ames, A. III. Dissociation of field potential from neuronal activity in the isolated retina; failure of the b-wave with normal ganglion cell response. In press, J. Neurobiol., May l975.